Abstract: In an example, a method includes determining, using a processor, a first halftone screen comprising a plurality of cells. Each of the cells may contain a predetermined pixel cluster pattern, and a centre position of a cluster pattern within a first cell may be different to a centre position of a cluster pattern within a second cell.

Abstract: In an example, a method includes determining, using a processor, a first halftone screen comprising a plurality of cells. Each of the cells may contain a predetermined pixel cluster pattern, and a centre position of a cluster pattern within a first cell may be different to a centre position of a cluster pattern within a second cell.

Abstract: Certain examples described herein relate to a method in which a model for predicting a characteristic of a printed halftone image is generated. The method may include receiving sets of image data, each representing a respective image. The sets of image data may include input image data representing the respective image using a halftone pattern, and corresponding printed image data representing a printed version of the respective image printed on the basis of the halftone pattern. A training process may be iteratively performed to train a neural network to generate a mapping between input image data and printed image data. The model may be generated on the basis of the mapping. An apparatus, a system and a non-transitory computer-readable storage medium are also described.

Abstract: A method comprises forming a halftone screen set comprising first, second and third halftone screens. A first regular halftone screen for the screen set is selected. A second regular halftone screen is determined, using a processor, by performing a regularity invariant transformation on the first regular halftone screen. A third halftone screen is determined based on at least one predetermined condition being satisfied between the first, second and third halftone screens.

Abstract: Certain examples described herein relate to the halftoning of a color image. In one example, a set of clusters are determined based on the color image. A set of edges are also detected in the color images. Clusters within these edges are then merged. A set of screens for halftoning are assigned to the set of clusters. This assignment is based on color property metrics for the set of clusters. The color image is halftoned using the set of screens assigned to the merged clusters.

Abstract: In an example, a method includes determining, using a processor, a set of halftone screens each comprising tiles spanning a plurality of cells, wherein at least one screen is a non-orthogonal screen and the cells comprise parallelograms being defined by a first vector having a first length and second vector having a second length. A first and a second fundamental frequency may be determined for each of the screens using a projection of the first and of the second vector into each axis of a print apparatus reference frame, the first length and the second length. Using the first and second fundamental frequencies, it may be determined which screens are associated with moiré effects below a threshold.

Abstract: A halftone comprises a first halftone screen and a second halftone screen. The first halftone screen comprises a first plurality of amplitude modulated dots arranged according to a first plurality of rows, the first plurality of rows being orientated according to a first direction and comprising a first dot spacing. The second halftone screen comprises a second plurality of amplitude modulated dots arranged according to a second plurality of rows, the second plurality of row being orientated in a second direction and comprising a second dot spacing. The first direction and the second direction define an angle of 45 degrees or less and a ratio of the second dot spacing to the first dot spacing is less than one.

Abstract: A halftone comprises a first halftone screen and a second halftone screen. The first halftone screen comprises a first plurality of amplitude modulated dots arranged according to a first plurality of rows, the first plurality of rows being orientated according to a first direction and comprising a first dot spacing. The second halftone screen comprises a second plurality of amplitude modulated dots arranged according to a second plurality of rows, the second plurality of row being orientated in a second direction and comprising a second dot spacing. The first direction and the second direction define an angle of 45 degrees or less and a ratio of the second dot spacing to the first dot spacing is less than one.

Abstract: A halftone comprises a first halftone screen and a second halftone screen. The first halftone screen comprises a first plurality of amplitude modulated dots arranged according to a first plurality of rows, the first plurality of rows being orientated according to a first direction and comprising a first dot spacing. The second halftone screen comprises a second plurality of amplitude modulated dots arranged according to a second plurality of rows, the second plurality of row being orientated in a second direction and comprising a second dot spacing. The first direction and the second direction define an angle of 45 degrees or less and a ratio of the second dot spacing to the first dot spacing is less than one.

Abstract: A halftone comprises a first halftone screen and a second halftone screen. The first halftone screen comprises a first plurality of amplitude modulated dots arranged according to a first plurality of rows, the first plurality of rows being orientated according to a first direction and comprising a first dot spacing. The second halftone screen comprises a second plurality of amplitude modulated dots arranged according to a second plurality of rows, the second plurality of row being orientated in a second direction and comprising a second dot spacing. The first direction and the second direction define an angle of 45 degrees or less and a ratio of the second dot spacing to the first dot spacing is less than one.